1. Field of the Invention
The present invention relates to a dust collecting apparatus adapted for use in various industrial plants such as a steel manufacturing plant, a cement plant, various kinds of chemical plants and the like for purifying high-temperature exhaust gases discharged therefrom, and more particularly to a support construction of a ceramic filter element adapted for use in the dust collecting apparatus.
2. Description of Prior Art
Disclosed in Japanese Patent Laid-open Publication No. 354506/1992 is a dust collecting apparatus of this kind which includes an upright housing provided at its upper portion with an inlet duct and at its bottom portion with a discharge duct. A ceramic filter assembly composed of a plurality of ceramic filter elements is aligned in parallel and mounted within the upright support housing to form an inlet chamber in open communication with the inlet duct and a discharge chamber in open communication with the discharge duct. Each of the filter elements is made of porous ceramic material and having a thin walled cellular structure formed with a plurality of axially extending passages separated from each other by thin partition walls, wherein a first group of axial passages are in the form of inlet passages closed at one end and open at the other end thereof to introduce exhaust gases supplied from the inlet chamber to be purified, while a second group of axial passages are in the form of outlet passages open at one end thereof to discharge purified gases therefrom into the discharge chamber and closed at the other end thereof. In the dust collecting apparatus, exhaust gases to be purified are introduced into the first group of axial inlet passages at an upstream side of the filter assembly so that the thin partition walls of the filter elements act to collect dust from the exhaust gases permeating therethrough from the first group of the axial inlet passages into the second group of axial outlet passages thereby to purify the exhaust gases.
In the dust collecting apparatus, each of the ceramic filter elements is enclosed by a sealing member and fixed in place within the upright housing through the sealing member to prevent leakage of exhaust gases passing therethrough. In such a support construction of the filter elements, however, the filling condition of the sealing member depends on the worker's skill. Accordingly, when exhaust gases under high pressure are supplied into the inlet chamber of the dust collecting apparatus, the sealing members tend to be moved toward a downstream side of the filter assembly by a difference in pressure between the inlet and discharge chambers. This causes undesired influence on the sealed condition of the filter elements. During a reverse washing process of the filter elements, the sealing members tend to be moved toward the upstream side of the filter assembly by the pressure of washing gas supplied into the downstream side of the filter elements.